Fluid Hatch Pattern — Harold Detlaff — A nice AutoCAD hatch pattern you can use to represent fluid. Click the tip title to see an example.
Draw Squares Based on Area — Kent Cooper — This LISP routine will draw squares in AutoCAD based on an area you supply in square units.
Auto-Elevate Polylines — Juan Villarreal — A nice routine that will help AutoCAD users working in the civil/survey fields. It elevates polylines in contour maps based on the associated elevation text label.
Draw Inner and Outer Splines from Plines — Amir Hossein Sattarian — When given a polyline, this AutoCAD routine will construct inner and outer splines whose vertices match those of the original selected polylines. Click the tip title to see an example.